copyright © 1997-2012 v&r energy systems research, inc. all rights reserved. 1 use of...

Copyright © 1997-2012 V&R Energy Systems Research, Inc. All rights reserved.1

Use of Node-Breaker Model in POM Suite/ROSE Software

Presented by Marianna Vaiman, V&R Energy

West Wide System Model and Basecase Reconciliation Task Force (WBRTF)

WECC WebEx MeetingAugust 22, 2012

V&R EnergyV&R Energy’s services include:– Comprehensive software tools for analyzing power system behavior

Vendor of POM Suite and ROSE applications– Advanced consulting services – Cutting edge scientific research

V&R is located in Los Angeles, CAI'm convinced you (plural) are the only ones in the industry giving the proper thought and attention to the problems that

transmission operators and planners are trying to manage– American Transmission Co.

V&R Energy’s software allows us to do in 20 minutes what normally takes about seven hours with our present system– East Kentucky Power

Copyright © 1997-2012 V&R Energy Systems Research, Inc. All rights reserved. 2

Physical and Operational Margins (POM) SuiteAvailable for real-time and off-line computationsExtremely fast:– 8 to 10 times faster than similar applications

Very reliable and robust solution engineVery flexible scriptingHandles extremely large contingency/fault lists:– Millions of N-1-1, N-2 contingencies during one simulation run– Hundreds of thousands of faults during one simulation run

Automates and expedites NERC compliance studiesPredicts and prevents cascading outagesOffers a boundary-based solutionAutomatically determines optimal corrective actions to mitigate exceeding operating limits


POM Suite - Planning


POM Suite Use in PlanningNERC-compliance studies:– NERC TPL Standards Compliance (TPL-003, TPL-004)

Steady State AnalysisTransient Stability Analysis

– NERC FAC-014 Standard ComplianceEstablishing System Operating Limits

– NERC PRC-023 Standard ComplianceIdentification of 100kV- 200kV transmission lines

– NERC MOD-001, 004, 006, 007, 008, MOD-028, 029, 030Available transfer capability


POM Suite Use in Planning (cont)Voltage stability analysis– AC transfer/load pocket and contingency analyses with visualization– Determines available transfer capability for each contingency– Determines interface flows– Automatically builds PV-curves

Transmission system expansion analysisReliability analysis– Using results of POM-OPM to compute reliability indices

Phase-shifter settings optimization to relieve post-contingency violationsAnalysis of cascading outages


POM Suite – Real Time/ROSE


Same algorithms for off-line and real-time analysisModel-based & measurement-based State EstimatorIntegrated voltage and transient stability analysesBoundary-based solutionAutomatic analysis of cascading outagesAutomatic remedial actions to mitigate steady-state & transientstability violations

POM Applications in Real-TimeUses of POM Suite in Real-Time include: – State Estimation,– Voltage stability analysis,–Massive AC contingency analysis with remedial actions– Use of PMU data to perform voltage stability analysis,

predict instability and alarm operators– Predicting cascading outages


Role of the Node-Breaker Model in POM Suite

Bridges real-time and off-line analysisPOM Suite/ROSE reads analysis includes:– Reading of export file in node-breaker model – Performing necessary topology processing– Performing steady-state analysis:

Voltage stability analysis, AC contingency analysis, RAS implementation, determining remedial actions, etc.

Automatic conversion of the node-breaker model to bus-branch model in Siemens PSS/E .raw file format for use in planning analysis– Saves the full model


POM Suite Integration with Other Applications

Easy integration with other applicationsReads node-breaker and bus-branch modelsNode-breaker:– Export (“flat”) files from an EMS system, – CIM-compatible

Bus-branch:– Power flow cases in PTI PSS/E rev. 23-32, GE-PSLF version 17

(and earlier), PowerWorld *.aux format

Solves and converts cases to POM internal formatModified power flow cases may be saved for future use


POM Program FunctionalitiesMain program of the PackagePerforms power flow computationsPerforms massive AC contingency analysis for large power system models: – Fast AC contingency analysis

Automatically generates contingency lists/reads existing listsAnalyzes N 1, N-1-1, and N 2 contingencies ‑ ‑Identifies critical contingencies and associated violations

Monitors user-defined constraints: – Simultaneously monitors voltage stability, voltage and thermal

constraints– Computes voltage stability margins

Simulates power transfers while monitoring constraints


Modes of POM OperationBasic Mode– Easy, fast computation of a particular

contingency, load scaling, simulation ofa power transfer

– Constraints are graphically displayed

Advanced Mode– Flexibility of analysis using POM

commands– Constraints are graphically displayed

Automatic Mode– Massive contingency analysis

Script Mode– Complete control of computations

and output


Determining Optimal Remedial Actions (System Adjustments)

Fast, powerful and efficient remedial actions toolAutomatically alleviates violations during massive AC contingency analysisIncreases operating marginsRAS is incorporated through scripting


Remedial Actions Used in OPMApplies a minimum amount of mitigation measures based on a user-defined priority scheduleAvailable remedial actions include:– MW Dispatch – MVar Dispatch – Capacitor and Reactor Switching– Transformer Tap Change – Phase Shifter settings– Line Switching (In and Out)

Switching Not Affected Lines – Load Curtailment – Optimal Capacitor, Reactor Placement and Size– OPM Operating Procedures


Analysis of Extreme Events

Automated analysisAnalysis scenario:– Quantify a power system’s ability to withstand cascading

outages due to thermal and/or voltage violations

Quickly identify initiating events that may lead to cascading events

Impractical to apply all N-k contingencies in a bulk power system

Automatically identify potential cascading modes


A Boundary-Based Solution

Automatically identifies the operating region that satisfies N-1/N-1-1/N-2 reliability criteria Finds AC limits for transfer scenarios based on voltage stability, voltage constraints, and thermal constraintsComputes dynamic security region


Automatically determines the most limiting contingencies – Secure operating region may be

formed by several contingencies The area formed by the most limiting contingencies is the area that satisfies N-1 and/or N-2 reliability criteria

Power system is secure only when operating within this area

– Can be used in real-time, on-line and planning environments

Operating Region that Satisfies Reliability Criteria


POM – Transient Stability (POM-TS)

Fast and user-friendly dynamic simulation – execution time for a one second simulation is approximately 6 seconds for a 50000 bus case and 17000 dynamic models Fully integrated into POMSupports Library of dynamic models in Siemens PTI’s PSS/E and GE’s PSLF formatsAllows for easy inclusion of user-defined models through use of POM scriptingSatisfies NERC/WECC criteriaPerforms fast fault screening in order to determine the most severe three-phase and unbalanced faults in the system


ROSE – PMU-based AnalysisRegion Of Stability Existence - ROSE defines the range of phasor measurements or other system parameters – For which the system may securely operate in terms of the accepted N-k

security criteria

Addresses the problem of utilizing the PMU data to increase the situation awareness of the operators and improve stability and reliability of the electric grid

For steady-state analysis: voltage stability, voltage constraint (voltage range and/or pre-to post contingency voltage drop) and thermal overloads may be simultaneously monitored, enforced and visualized on the boundaryFor steady-state stability has two inputs: node-breaker or bus-branch model

Combinatory approach– Combines model-based (State Estimator data) and measurement-based (PMU

data) computations


Use of Node-Breaker Model for Steady-State Stability Analysis

POM Suite/ROSE is used for steady-state analysis in real-time and off-line environments, including:– Voltage stability analysis:

Runs multiple user-defined scenarios;Computations performed for each scenario are:

– Determining interface limits;– Performing PV-curve analysis;– Performing VQ-curve analysis.

– Automatic AC contingency analysis;– Reading of existing RAS;– Automatically determining optimal remedial actions as an advisory function for

operators

Never collapses buses during its analysis– Always uses FULL NON-CONSOLIDATED MODEL– Very strong solution engine


Steady-State Voltage Stability Analysis Using Node-Breaker Model

PV-Curve and VQ-Curve are most frequently used steady-state techniques for voltage stability assessment– At selected buses

PV-curve analysis– Stresses the system in terms

of load increase, power transfer and computes post-contingency voltages

– Multiple power flow computationsto determine the stability margin

VQ-curve analysis:– Adding a fictitious condenser bus– V is independent variable,

Q injection is dependent– Provides a set of scheduled voltages

at a bus


Reading Node-Breaker Model in POM Suite/ROSE

As export “flat” file isbeing loaded, its summary is displayedon the interfaceAs POM reads the export file and contingency lists, it performs topology processing– Generates a file that

lists buses that were split and how they were split as a result of contingencies


Displaying Node-Breaker Model in POM Suite/ROSE

After export “flat” file isbeing loaded, it is displayedin the form of:– POM Data Tables– One-lines that are

automatically built


Use of Node-Breaker Model for Voltage Stability Analysis

Node-breaker representation is used to:– Determine import

limits on the interfaces



Node-breaker representation is used to:– Compute and plot

PV-Curves



Node-breaker representation is used to:– Compute and plot

VQ-Curves


Use of Node-Breaker Model for Analysis of a Particular Contingency

A particularcontingency maybe furtheranalyzed: – On the base

case– While stressing

the system interms of a power transfer, load scaling, etc.


Use of Node-Breaker Model for Determining Remedial Actions

Remedial actions may be further developed to:– Alleviate post-contingency violations

Voltage stability, voltage, thermal– Increase operating margins


Use of Node-Breaker Model for Automatic Contingency Analysis

Automatic massive AC contingency analysis may be performed– N-1, N-2 contingency analysis– RAS enabled/disabled– Post-contingency remedial actions may be automatically

determined during massive computations– Critical contingencies, post-contingency violations and remedial

actions reported


Challenges of Using Node-Breaker Model

Not a formal database:– Complex procedures for reading/processing of export “flat” file

Utilities/ISOs do not usually use this format internally


Advantages of Using Node-Breaker Model in POM Suite

Accurate representation of the real-time system:– An actual State Estimator snapshot

Accurate real-time contingency analysis:– Buses may be split, if necessary

Breakers are not being collapsed during power flow solutionExport file from EMS may be saved as a bus-branch model (in PSS/E .raw format):– All breakers are kept in the model as zero-impedance lines

Node-breaker model is used in POM Suite for:– Voltage stability, contingency analysis, system stressing (power

transfer simulation, load scaling), RAS actions, any power flow computation


Thank you!


copyright © 1997-2012 v&r energy systems research, inc. all rights reserved. 1 use of...

Documents

analysis pom suiterose

vr energy systems research

planning analysis

pom applications

pom suite use

pom suite planning copyright

vr energy vr energys

steadystate analysis